Shaded pole motor



March 6, 1951 Q WALWQRTH JR 2,543,816

SHADED POLE MOTOR Original Filed Aug. 18, 1945 Patented Mar. 6, 1951 Clarence B. Walworth, J r., Rocky Hill, Conn.

Original application August 18, 1945, Serial No. 611,276, now Patent No. 2,445,813, dated July 27, 1948. Divided and this application July 14, 1948, Serial No. 38,583

4 Claims.

This invention pertains to electric motors, particularly to reaction type synchronous motors such as are employed, for example, for driving clock or relay mechanisms. The present application is a division of my copending application Serial Number 611,276, filed August 18, 1945, now Patent No. 2,445,813 dated July 2'7, 1948.

The principal object of the present invention is to provide a motor of this type which is of very simple construction employing a minimum number of parts and which may be made in very small sizes if desired, but which is rugged and durable, has good starting characteristics and is capable of delivering a high torque. A further object is to provide a motor of this type most of whose parts may be made from sheet material by simple stamping or die press operations, which may readily be assembled without requiring high skill, and which may be provided with shading coils of a simple and highly effective construction. Still another object is to provide such a motor which has favorable operating conditions due to a peculiar correlation of the pole elements of the energizing member and a shading coil.

These and other objects and advantages will be pointed out in the following more detailed description of several embodiments illustrating the characteristic features of the invention with reference to the accompanying drawings, wherein Fig. 1 is a diametrical section through one embodiment of the invention;

Fig. 2 is a top view of the motor according to Figs. 1 and 3 with the rotor removed and part of the upper shading members broken away;

Fig. 3 is a fragmentary isometric view of the stator shell according to Fig. 1; and

Fig. 4 is a fragmentary radial section of an additional embodiment of the invention.

As shown in Figs. 1 and 2, the stator element of one embodiment, which is included in the subject matter of the present divisional application, consists of a single stamping 332. As particularly indicated in Fig. 3, the pole teeth extend upwardly from the two concentric edges of the half-doughnut shaped stator body, such that pairs of outer pole teeth 335, 3-56, are placed symmetrically to the direction of the radii extending halfway between inner pole teeth pairs, 363, 364. The stator body is closed, and the magnet coil 35!! kept in place, by shading disks em which, with the exception of the lowest disk 31 I, have an annular shape (with projections 3'55, 3'56 (Fig. 2) extending outw dly and inwardly, respectively. The pole teeth and 334 respectively, are shaded, whereas teeth 333 and 355 are electrically not affected.

As indicated in Fig. 2, the lowest shading disk 3' has circular openings 318 which perform the function of the corresponding recesses of the upper shading disk, and a central opening 31.9 (Fig. 1) for the mounting shaft 339. The disk 342 supports the bearing block 385 which may again comprise a ball bearing or be made of porous oilsaturated metal, and which is fastened to disk 3H by means of a nut 345, as indicated in Fig. 1.

The rotor construction shown in Fig. 1 is similar to the embodiment shown in Fig. 1 in my Patent No. 2,445,813, with the difference that the rotor proper is in this case a plane disk 335, fastened to bearing block 385 by means of press fitted gear block 386. The entire motor assembly may be fastened to the supporting structure 353a by means of bolt extension 339 and nut 349.

The magnetic flux again surrounds coil 353, closing through the teeth and the peripheral por tion of rotor disk 380 A further embodiment of the present invention is indicated in Fig. 4. This construction is rather similar to that described above with reference to Figs. 1 to 3, with the exception that, instead of being pressed from a single sheet, the stator structure consists of a fiat disk 432, to which are welded at 433 and 434 two cylindrical teeth-carrying rings 438 and 439.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. An electric motor of the type described comprising a substantially circular hollow half-toroid shaped motor body forming an annular groove with two concentric toothed edge portions, conductor means shading alternate teeth of said edge portions, an energizing coil held in said groove by said conductor means, a second substantially circular disk-shaped motor body, and means for mounting said second body on said first body for concentric rotation relatively thereto, the peripheral portion of said second body bridging said edge portions of said first body.

2. An electric motor of the type described comprising a sheet steel body in the shape of an annular groove with edge portions extending substantially cylindrically from said groove, pole teeth formed integrally with said edge portions in pairs angularly alternating on said edge portions, shading means engaging said teeth with alternate teeth being wholly surrounded by said shading means, and an energizing coil confined in said groove.

3. An electric motor of the type described comprising a sheet steel body in the shape of a substantially U-shaped annular groove, with edge portions extending substantially oylindrically from said groove, pole teeth formed integrally with said edge portions in pairs angularly alternating on said edge portions, shading plate means engaging said teeth with alternate teeth being wholly surrounded and hence magnetically affected and incompletely surrounded and hence magnetically unaffected, respectively, by said shading means, an energizing coil confined in said groove, a bearing fixed to said shading means in the axis of said groove, and a rotor disk rotatably mounted on said bearing with its peripheral re- 15 gion bridging said teeth.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 391,565 Great Britain May 4, 1933 415,168 Great Britain Aug. 23, 1934 581,378 Germany July 26, 1933 623,239 Germany Dec. 20, 1935 

